1. Field Of the Invention
The present invention relates generally to a light transmission system for use on a vehicle and more specifically to an illuminator for use as a vehicle headlight or taillight.
2. Description Of the Related Art
Conventional light transmission systems used for vehicle headlights or taillights typically utilize a bulb and reflector system. In a bulb and reflector system, a filament of the bulb is placed at or near a focal point of a reflector. The light emitted by the bulb filament is collected by the reflector and reflected outward to form a light beam. A lens is used to shape the light beam into a specified pattern as established by vehicle lighting standards. Typically, a conventional bulb and reflector system collects and reflects only thirty percent of the light emitted from the bulb filament.
Bulb and reflector systems have several disadvantages, including aerodynamic and aesthetic styling; e.g., the depth of the reflector along its focal axis and the dimensions of the reflector in directions perpendicular to the focal axis have greatly limited attempts at streamlining the front end of the vehicle. Additionally, the thermal energy given off by the bulb during operation must be considered as the size of the reflector and the material used in its construction vary depending upon the amount of thermal energy radiating from the bulb filament. Decreasing the size of the reflector requires an increase in the thermal resistivity of the reflector material.
One approach to developing a headlight for use with the newer streamlined body designs is proposed in U.S. Pat. No. 4,432,039 which discloses an elliptical reflector used to concentrate and focus light on a light bar having a plurality of reflective facets. While this approach may be useful, a certain portion of the light from the reflector escapes reflection at the facets, thus lowering the efficiency of the headlight. Additionally, the headlight requires the use of lens optics to focus the light reflected by the facets.
Thus, there is a need in the art for an efficient low profile illuminator which accommodates both thermal considerations and the space limitations dictated by the vehicular aerodynamic and styling requirements.